First footage from The CW's Flash, Arrow and Legends of Tomorrow crossover

The CW's roster of DC heroes will face their toughest task yet at the end of this month — and here’s a first look at arguably the most ambitious crossover in television history.

The network is gearing up for a four-show crossover event featuring Supergirl, Flash, Arrow and Legends of Tomorrow. The combined group of heroes will face off against The Dominators, a group of mind-controlling extraterrestrials who apparently attack Earth due to the planet’s growing population of metahumans. The first, all-too-brief promo seems to show Barry Allen introducing Supergirl to the rest of his world’s heroes (maybe he returns to Supergirl’s Earth to recruit her for the mission?).

It might seem obvious, but it is insanely cool to see all these characters sharing the same scene. Yes, The CW has staged crossovers before, but nothing this big. Ever. A massive story that spreads across four shows? That’s huge. It’s also a proving ground for events like this moving forward, and if the ratings are solid across the board, expect even more of these in the future.

The entire event kicks off Monday, Nov. 28, on Supergirl, then continues throughout the week on the other affected shows.

Entertainment Weekly’s photo spread (pick up the latest issue for more) featuring several of the stars is also included below (which are great geek fodder). There are also a few shots from the episodes themselves, and we see the surprising return of Laurel Lance, plus a shot of Diggle seemingly hunting for Green Arrow and Flash (a bit of that trademark alien mind-control on display, perhaps?).